[slime-devel] Re: Broken readtables

[Martin Simmons]

>>>>> On Thu, 17 Jun 2004 18:56:58 +1000, Alain.Picard at memetrics.com said:

  ap> Luke Gorrie writes:
  >> Alain.Picard at memetrics.com writes:
  >> 
  >> > I have a file which defines a readtable so I can type
  >> > things like #v(1 2).  (Don't ask.  :-)
  >> >
  >> > When I hit M-. to find any definition in this file, emacs
  >> > croaks and asks if I want to enter recursive edit.  Saying
  >> > yes yields a SLDB buffer like this:
  >> 
  >> The `with-standard-io-syntax' in dspec-stream-position looks
  >> suspicious to me (swank-lispworks.lisp). How about if you remove it?
  >> 
  ap> If you remove it, it works.  In fact, I think there are TWO bugs
  ap> in that function; I think that *read-eval* needs to be set to T.

It was bound it to NIL to prevent unexpected evaluation -- it depends on how
dangerous you want M-. to be :-)

#.(call-system "rm -rf /")


  ap> I propose:

  ap> (defun dspec-stream-position (stream dspec)
  ap>   (let ((*read-eval* t))
  ap>     (loop (let* ((pos (file-position stream))
  ap>                  (form (read stream nil '#1=#:eof)))
  ap>             (when (eq form '#1#)
  ap>               (return nil))
  ap>             (labels ((check-dspec (form)
  ap>                        (when (consp form)
  ap>                          (let ((operator (car form)))
  ap>                            (case operator
  ap>                              ((progn)
  ap>                               (mapcar #'check-dspec
  ap>                                       (cdr form)))
  ap>                              ((eval-when locally macrolet symbol-macrolet)
  ap>                               (mapcar #'check-dspec
  ap>                                       (cddr form)))
  ap>                              ((in-package)
  ap>                               (let ((package (find-package (second form))))
  ap>                                 (when package
  ap>                                   (setq *package* package))))
  ap>                              (otherwise
  ap>                               (let ((form-dspec (dspec:parse-form-dspec form)))
  ap>                                 (when (dspec:dspec-equal dspec form-dspec)
  ap>                                   (return pos)))))))))
  ap>               (check-dspec form))))))

  ap> in swank-lispworks.lisp.

I made it use WITH-STANDARD-IO-SYNTAX originally to get all the standard
bindings, in particular you must also bind *PACKAGE* because the function sets
it.  There is also *READ-BASE*, *READ-DEFAULT-FLOAT-FORMAT* and
*READ-SUPPRESS* to consider.

What binds *READTABLE* when you do M-. anyway?  It doesn't seem to be bound
for me when DSPEC-STREAM-POSITION is reached via FIND-DEFINITIONS-FOR-EMACS.

__Martin